{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,3]],"date-time":"2026-03-03T16:11:49Z","timestamp":1772554309220,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,6]],"date-time":"2022-01-06T00:00:00Z","timestamp":1641427200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002367","name":"Chinese Academy of Sciences","doi-asserted-by":"publisher","award":["XAB2018B21"],"award-info":[{"award-number":["XAB2018B21"]}],"id":[{"id":"10.13039\/501100002367","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Time Service Center","award":["Y917SC1S08"],"award-info":[{"award-number":["Y917SC1S08"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The eLoran system is an international standardized positioning, navigation, and timing service system, which can complement global navigation satellite systems to cope with navigation and timing warfare. The eLoran receiver measures time-of-arrival (TOA) through cycle identification, which is key in determining timing and positioning accuracy. However, noise and skywave interference can cause cycle identification errors, resulting in TOA-measurement errors that are integral multiples of 10 \u03bcs. Therefore, this article proposes a cycle identification method in the joint time\u2013frequency domain. Based on the spectrum-division method to determine the cycle identification range, the time\u2013domain peak-to-peak ratio and waveform matching are used for accurate cycle identification. The performance of the method is analyzed via simulation. When the signal-to-noise ratio (SNR) \u2265 0 dB and skywave-to-groundwave ratio (SGR) \u2264 23 dB, the success rate of cycle identification is 100%; when SNR \u2265 \u221213 dB and SGR \u2264 23 dB, the success rate exceeds 75%. To verify its practicability, the method was implemented in the eLoran receiver and tested at three test sites within 1000 km using actual signals emitted by an eLoran system. The results show that the method has a high identification probability and can be used in modern eLoran receivers to improve TOA-measurement accuracy.<\/jats:p>","DOI":"10.3390\/rs14020250","type":"journal-article","created":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T23:08:26Z","timestamp":1641769706000},"page":"250","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["An eLoran Signal Cycle Identification Method Based on Joint Time\u2013Frequency Domain"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7534-5706","authenticated-orcid":false,"given":"Wenhe","family":"Yan","sequence":"first","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ming","family":"Dong","sequence":"additional","affiliation":[{"name":"Beijing Institute of Tracking and Telecommunications Technology, Beijing 100094, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shifeng","family":"Li","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7839-1502","authenticated-orcid":false,"given":"Chaozhong","family":"Yang","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiangbin","family":"Yuan","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3771-0319","authenticated-orcid":false,"given":"Zhaopeng","family":"Hu","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu","family":"Hua","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,6]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"Analysis on underwater PNT system and key technologies","volume":"4","author":"Xu","year":"2017","journal-title":"Navig. Position. Timing"},{"key":"ref_2","first-page":"6","article-title":"Prospects for development of loran-C navigation system for building up national comprehensive PNT system","volume":"40","author":"Zhang","year":"2020","journal-title":"J. Astronaut. Metrol. Meas."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1007\/s10291-018-0702-5","article-title":"Railay irregularity measuring using rauch-tung-striebel smoothed multi-sensors fusion system: Quad-GNSS PPP, IMU, odometer, and track gauge","volume":"22","author":"Gao","year":"2018","journal-title":"GPS Solut."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"11369","DOI":"10.3390\/s101211369","article-title":"Reliable location-based services from radio navigation systems","volume":"10","author":"Di","year":"2010","journal-title":"Sensors"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Specht, M. (2021). Determination of navigation system positioning accuracy using the reliability method based on real measurements. Remote Sens., 13.","DOI":"10.3390\/rs13214424"},{"key":"ref_6","first-page":"11","article-title":"Determination of the precise coordinates of the GPS reference station in of a GBAS system in the air transport","volume":"22","author":"Krasuski","year":"2020","journal-title":"Commun. Sci. Lett. Univ. Zilina"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1719","DOI":"10.1109\/LAWP.2019.2926734","article-title":"Experimental study on a modified method for propagation delay of long wave signal","volume":"18","author":"Li","year":"2019","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1017\/S0373463315000879","article-title":"A History of maritime radio-navigation positioning systems used in Poland","volume":"69","author":"Specht","year":"2016","journal-title":"J. Navig."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1002\/navi.197","article-title":"Providing a resilient timing and UTC service using eLoran in the United States","volume":"64","author":"Offermans","year":"2017","journal-title":"Navig. J. Inst. Navig."},{"key":"ref_10","first-page":"100","article-title":"Navigation warfare and its countermeasures","volume":"8","author":"Ren","year":"2020","journal-title":"J. Navig. Pos."},{"key":"ref_11","first-page":"6","article-title":"Analysis on the disadvantage of American navigation and timing warfare","volume":"6","author":"Ge","year":"2020","journal-title":"Aerodyn. Missile J."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Wang, X.Y., Zhang, S.F., and Sun, X.W. (2017). The additional secondary phase correction system for AIS signals. Sensors, 17.","DOI":"10.3390\/s17040736"},{"key":"ref_13","unstructured":"(2021, October 15). Strategy for the Department of Defense Positioning, Navigation and Timing (PNT) Enterprise\u2014Ensuring a US Military PNT Advantage. Available online: https:\/\/rntfnd.org\/wp-content\/uploads\/DoD-PNT-Strategy.pdf."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Yan, W.H., Zhao, K.J., Li, S.F., Wang, X.H., and Hua, Y. (2020). Precise loran-C signal acquisition based on envelope delay correlation method. Sensors, 20.","DOI":"10.3390\/s20082329"},{"key":"ref_15","unstructured":"(2021, October 18). About the Main Directions (Plan) of the Development of Radio Navigation CIS Member States for 2019\u20132024. Available online: https:\/\/rntfnd.org\/wp-content\/uploads\/CIS-Russia-Radionav-Plan-2019-2024.pdf."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"193708","DOI":"10.1109\/ACCESS.2020.3033215","article-title":"eLoran: Resilient positioning, navigation, and timing infrastructure in maritime areas","volume":"8","author":"Son","year":"2020","journal-title":"IEEE Access"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"115042","DOI":"10.1109\/ACCESS.2021.3105063","article-title":"eLoran: Enhanced accuracy simulator for a future Korean nationwide eLoran system","volume":"9","author":"Rhee","year":"2021","journal-title":"IEEE Access"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3443","DOI":"10.1109\/TAP.2020.3037749","article-title":"Field-strength variations of LF one-hop sky waves propagation in the earth-ionosphere waveguide at short ranges","volume":"69","author":"Zhou","year":"2021","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"306","DOI":"10.1049\/ip-f-2.1992.0043","article-title":"Effect of skywave interference on the coverage of loran-C","volume":"139","author":"Last","year":"1992","journal-title":"IEE Proc. F-Radar Signal Process."},{"key":"ref_20","first-page":"1644","article-title":"Digital algorithm realized with SOPC for cycle identification of Loran-C","volume":"37","author":"Zou","year":"2005","journal-title":"J. Harbin Inst. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1109\/7.826332","article-title":"Loran-C cycle identification in hard-limiting receivers","volume":"36","author":"Fisher","year":"2000","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_22","first-page":"20","article-title":"A novel signal search algorithm for loran-C receiver","volume":"47","author":"Yan","year":"2010","journal-title":"Electron. Technol."},{"key":"ref_23","unstructured":"Yan, W.H., Hua, Y., Yuan, J.B., Zhao, K.J., and Li, S.F. (2017, January 20\u201322). A ioint detection method of cycle-identification for loran-C signal. Proceedings of the 2017 13th IEEE International Conference on Electronic Measurement & Instruments (ICEMI), Yangzhou, China."},{"key":"ref_24","first-page":"81","article-title":"Algorithm of matching wave for cycle identification of LORAN-C","volume":"167","author":"Lin","year":"2008","journal-title":"Ship Electron. Eng."},{"key":"ref_25","first-page":"115","article-title":"Improved Loran-C joint identification algorithm for sky-ground wave and cycle based on optimized envelope","volume":"43","author":"Sui","year":"2020","journal-title":"Electron. Meas. Technol."},{"key":"ref_26","first-page":"547","article-title":"Joint cycle-identification method for Loran-C signal","volume":"35","author":"Li","year":"2014","journal-title":"J. Jiangsu Univ."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1049\/el:19950072","article-title":"Loran-C skywave delay estimation using eigen-decomposition techniques","volume":"31","author":"Bian","year":"1995","journal-title":"eLectronics Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2217","DOI":"10.1049\/el:19981571","article-title":"Loran-C skywave delay estimation using the AR algorithm","volume":"34","author":"Mohammed","year":"1998","journal-title":"eLectronics Lett."},{"key":"ref_29","first-page":"1153","article-title":"A New Loran C Sky-wave and ground-wave identification algorithm based on IFFT spectral division","volume":"31","author":"Zhu","year":"2009","journal-title":"J. Electron. Inf. Technol."},{"key":"ref_30","first-page":"7","article-title":"Loran-C receiver sky-wave detection based on MUSIC algorithms","volume":"18","author":"Hu","year":"2006","journal-title":"J. Nav. Aeronaut. Astronaut. Univ."},{"key":"ref_31","unstructured":"U.S. Coast Guard and the U.S. Coast Guard Auxiliary (2021, October 13). Loran-C User Handbook. Available online: https:\/\/www.loran.org\/otherarchives\/-1992%20-Loran-C%20User%20Handbook%20-%20USCG.pdf."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1109\/MAES.2007.4350283","article-title":"Loran data modulation: A primer","volume":"22","author":"Lo","year":"2007","journal-title":"IEEE Aerosp. Electron. Syst. Mag."},{"key":"ref_33","first-page":"1407","article-title":"Research of Loran-C data demodulation and decoding technology","volume":"33","author":"Li","year":"2012","journal-title":"Chin. J. Sci. Instrum."},{"key":"ref_34","first-page":"1606","article-title":"Study on time delay characteristics of low frequency one-hop sky waves in the isotropic ionosphere","volume":"42","author":"Zhou","year":"2020","journal-title":"J. Electron. Inf. Technol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"986","DOI":"10.1109\/TEMC.2005.854099","article-title":"Characterization of 100-kHz noise in the lightning current derivative signals measured at the CN tower","volume":"47","author":"Liatos","year":"2005","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_36","unstructured":"Minimum Performance Standards for Marine eLORAN Receiving Equipment (2021, October 11). Radio Technical Commission for Maritime Services. Available online: https:\/\/rtcm.myshopify.com\/collections\/maritime-navigation-equipment-standards\/products\/copy-of-differential-gnss-package-both-of-the-current-standards-10402-3-and-10403-3."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2648","DOI":"10.1109\/TIM.2010.2096970","article-title":"Accuracy Improvement technique for timing application of LORAN-C signal","volume":"60","author":"Yang","year":"2011","journal-title":"IEEE Trans. Instrum. Measurement"},{"key":"ref_38","first-page":"317","article-title":"A new algorithm for sky-wave and ground-wave detection of loran C based on FFT\/IFFT technology","volume":"24","author":"Wu","year":"2009","journal-title":"J. Nav. Aeronaut. Astronaut. Univ."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Li, C., Zhen, J., Chang, K., Xu, A., Zhu, H., and Wu, J. (2021). An indoor positioning and tracking algorithm based on angle-of-arrival using a dual-channel array antenna. Remote Sens., 13.","DOI":"10.3390\/rs13214301"},{"key":"ref_40","first-page":"1","article-title":"Skywave delay estimation of Loran C based on modern signal processing methods","volume":"31","author":"Wu","year":"2011","journal-title":"Hydrogr. Surv. Charting"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/2\/250\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:26:56Z","timestamp":1760362016000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/2\/250"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,1,6]]},"references-count":40,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["rs14020250"],"URL":"https:\/\/doi.org\/10.3390\/rs14020250","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,1,6]]}}}